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Abstract:

To provide a working unit ejecting mist of the excellent quality. A
working unit includes a body, a ram, a forward and backward moving
mechanism moving the ram forward and backward, a tool, a holding section
holding the tool and moving forward and backward integrally with the ram,
a spindle motor rotating the holding section, and a mist supply portion
supplying mist mixed with air and cutting oil to the tool and works a
workpiece while supplying the mist. The tool has through-holes supplying
the mist to a cutting blade portion. The holding section includes a
collet holding the tool and a collet having an inner cylindrical portion
into which the collet is inserted with a communication hole to which the
mist supplied from the mist supply portion 10 is introduced being formed
from the inner cylindrical portion to an outer peripheral portion. A flow
path guide plug having a mist supply path formed from an inner opening
end of the communication hole toward the through-holes of the tool is
internally fitted to the inner cylindrical portion.

Claims:

1. A working device for working a workpiece using mist for working,
comprising: a generally cylindrical body; a ram provided inside the body
so that the ram can move forward and backward therein; a forward and
backward moving mechanism moving the ram forward and backward; a tool for
working the workpiece; a holding section holding the tool and moving
forward and backward integrally with the ram; a spindle motor rotating
the holding section; and a mist supply portion supplying foggy mist
generated by mixing air from an air supply section supplying the air and
cutting oil from an oil supply section supplying the cutting oil to the
tool, wherein: the tool has through-holes supplying the mist to a cutting
blade portion; the holding section includes a collet holding the tool and
a collet holder having an inner cylindrical portion into which the collet
is inserted with a communication hole to which the mist supplied from the
mist supply portion is introduced being formed from the inner cylindrical
portion to an outer peripheral portion; and a flow path guide plug having
a mist supply path formed from an inner opening end of the communication
hole toward the through-holes of the rear end surface of the tool is
internally fitted to the inner cylindrical portion.

2. The working device according to claim 1, wherein: the communication
hole is formed diagonal with respect to the axial direction from an outer
opening end formed on the outer peripheral surface of the collet holder
toward the inner opening end; the mist supply path is formed diagonal
with respect to the axial direction through an upstream side opening end
and a downstream side opening end toward the through-holes of the rear
end surface of the tool; and the flow path guide plug is arranged so that
the mist having entered an outer opening end continuously flows from the
communication hole to the through-holes of the tool through the mist
supply path.

3. The working device according to claim 1, wherein: the inner
cylindrical portion is provided with a connector connecting the collet
holder and a spindle in a step portion; and a rubber member firmly fixed
to the connector or the flow path guide plug is provided between the
connector and the flow path guide plug.

4. The working device according to claim 1, wherein the collet holder is
provided with a positioning pin for aligning the position of the
communication hole formed in the collet holder and the position of the
mist supply path formed in the flow path guide plug.

5. The working device according to claim 1, wherein an inside diameter of
the mist supply path is 1-3 mm.

6. The working device according to claim 1, wherein: the forward and
backward moving mechanism is formed of an air cylinder mechanism driven
by air supplied from an compressed air supply source; the spindle motor
is formed of an air motor driven by air supplied from the compressed air
supply source; and the air supply section is supplied with air supplied
from the compressed air supply source.

7. The working device according to claim 1, further comprising a flow
rate adjusting section adjusting the flow rate of the air supplied to the
mist supply portion and the cutting oil.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a working unit, working device
working a workpiece using mist generated by mixing air and cutting oil.

[0003] 2. Description of the Related Art

[0004] Conventionally, in cutting work or grinding work, with respect to
the method for supplying cutting oil (coolant) to a workpiece and a tool,
there have been two kinds in general of a method of supplying the cutting
oil through a space arranged inside a machine tool or a drilling unit
(so-called center-through and spindle-through) and a method of supplying
the cutting oil from a cutting oil supply unit arranged outside
(so-called side-through and side fluid supply).

[0005] With respect to the center-through and spindle-through unit, two
types are known, they are, one type blowing the foggy mist which is the
mixture of the cutting oil and air to the tool and workpiece from behind
the working unit in order to reduce friction, to lower the cost and the
like, and another type respectively supplying the cutting oil and air
from behind the working unit through the spindle and the outer periphery
and the side of the spindle and blowing them to the tool and workpiece
(for example, refer to Japanese Published Unexamined Patent Application
Nos. 2006-316801 (refer to claim 1 and FIG. 1) and H11-320327 (refer to
claim 1 and FIGS. 1, 2)).

[0006] Also, with respect to the side-through and side fluid supplying
unit, a type connecting a cooling mist supply unit to the side of the
tool at the leading end of the working unit in order to facilitate
replacement of the tool, to improve working accuracy and the like and
blowing the mist to the tool and workpiece is known (for example, refer
to Japanese Published Unexamined Patent Application Nos. 2002-178207
(refer to claim 1 and FIG. 5) and 2008-207290 (refer to FIG. 1)).

[0007] However, in the past, in a drilling unit of a construction in which
the center-through and spindle-through types could not be adopted, the
side-through system was adopted. At that time, when there were a number
of positions where the mist collided with the wall surface of the
drilling unit, when the mist was hard to enter into a through-hole of a
drill, or when the space volume inside a flow path where the mist flowed
changed largely, there was a case that the mist was liquefied, the
cutting oil accumulated inside, and only the air was ejected from the tip
of the drill.

[0008] In this case, when a predetermined amount or more of the cutting
oil was stored inside the drilling unit, there was a problem that the
liquid of the cutting oil liquefied from the mist was intermittently
discharged from the tip of the drill.

SUMMARY OF THE INVENTION

[0009] Accordingly, the present invention has been developed in order to
solve such problems, and an object of the present invention is to provide
a working unit, working device that allows ejection of the mist of the
excellent quality from the tip of a tool.

[0010] In order to address the above-described problems, according to a
first aspect of the present invention, a working unit, working device for
working a workpiece using mist for working includes a generally
cylindrical body, a ram provided inside the body so that the ram can move
forward and backward therein, a forward and backward moving mechanism
moving the ram forward and backward, a tool for working the workpiece, a
holding section holding the tool and moving forward and backward
integrally with the ram, a spindle motor rotating the holding section,
and a mist supply portion supplying foggy mist generated by mixing air
from an air supply section supplying the air and cutting oil from an oil
supply unit supplying the cutting oil to the tool, in which the tool has
through-holes supplying the mist to a cutting blade portion, the holding
section includes a collet holding the tool and a collet holder having an
inner cylindrical portion into which the collet is inserted with a
communication hole to which the mist supplied from the mist supply
portion is introduced being formed from the inner cylindrical portion to
an outer peripheral portion, and a flow path guide plug having a mist
supply path formed from an inner opening end of the communication hole
toward the through-holes of the rear end surface of the tool is
internally fitted to the inner cylindrical portion.

[0011] According to such a configuration, in the working unit, a
communication hole to which the mist is introduced is formed in the
collet holder having the inner cylindrical portion into which the collet
holding the tool is inserted from the inner cylindrical portion to the
outer peripheral portion. The flow path guide plug having the mist supply
path formed from the inner opening end of the communication hole toward
the through-holes of the rear end surface of the tool is internally
fitted to the inner cylindrical portion, the communication hole and the
mist supply path communicate with each other to allow the mist to flow
directly toward the through-holes of the tool. Thus, the mist supplied to
the communication hole of the collet holder flows straight to the
through-holes of the tool through the mist supply path of the flow path
guide plug and directly enters the through-holes, and therefore smooth
injection from the tip surface of the tool is allowed. As a result of it,
the working unit can work while ejecting the mist of the excellent
quality, and the workpiece can be finished smoothly with the excellent
surface roughness.

[0012] According to a second aspect of the present invention, in the
working unit, the communication hole may be formed diagonal with respect
to the axial direction from an outer opening end formed on the outer
peripheral surface of the collet holder toward the inner opening end, the
mist supply path may be formed diagonal with respect to the axial
direction through an upstream side opening end and a downstream side
opening end toward the through-holes of the rear end surface of the tool,
and the flow path guide plug may be arranged so that the mist having
entered an outer opening end continuously flows from the communication
hole to the through-holes of the tool through the mist supply path.

[0013] According to such a configuration, the communication hole and the
mist supply path are formed diagonal with respect to the axial direction
from the upstream side opening end toward the downstream side opening
end, and are arranged so that the mist having entered the outer opening
end of the communication hole continuously flows from the communication
hole to the through-holes of the tool through the mist supply path. Thus,
the mist supplied to the communication hole of the collet holder is
allowed to flow straight toward the through-holes of the tool via the
shortest distance, and collision of the mist with the inner wall and the
like of the flow path can be minimized as much as possible. As a result
of it, in the communication hole and the mist supply path, the flowing
resistance of the mist flowing through the flow path inside the holding
section can be reduced to make the flow smooth, and the mist can be
supplied into the tool while maintaining an excellent foggy state.

[0014] Also, because the mist supply path of the flow path guide plug
inserted into the inner cylindrical portion of the collet holder is
continuously arranged from the inner opening end of the communication
hole of the collet holder toward the through-holes of the rear end
surface of the tool, the spatial volume of the flow path can be reduced.
Accordingly, even when the liquefied cutting oil is generated inside the
flow path, the cutting oil can be inhibited from being stored inside the
flow path.

[0015] According to a third aspect of the present invention, in the
working unit, the inner cylindrical portion may be provided with a
connector connecting the collet holder and a spindle in a step portion,
and a rubber member firmly fixed to the connector or the flow path guide
plug may be provided between the connector and the flow path guide plug.

[0016] According to such a configuration, because the rubber member is
interposed between the connector and the flow path guide plug, the space
inside the inner cylindrical portion can be reduced, and formation of
unnecessary internal space inside the flow path can be suppressed. Also,
the tool is inserted to the inner cylindrical portion of the collet
holder in the axial direction with the flow path guide plug and the
rubber member being interposed in between, and is elastically supported.
Therefore, deterioration of centering accuracy of the tool caused by
drawing in of the collet and the tool in fastening a collet nut can be
prevented by the rubber member.

[0017] According to a fourth aspect of the present invention related, in
the working unit, the collet holder may be provided with a positioning
pin for aligning the position of the communication hole formed in the
collet holder and the position of the mist supply path formed in the flow
path guide plug.

[0018] According to such a configuration, because the position of the
communication hole and the position of the mist supply path are aligned
with each other by the positioning pin and the flow path guide plug is
fixed to the rotational direction of the collet holder, positions of the
both can easily agree with each other, and misalignment of the both can
be eliminated.

[0019] In the working unit, according to a fifth aspect of the present
invention, an inside diameter of the mist supply path may be 1-3 mm.

[0020] According to such a configuration, because the inside diameter of
the mist supply path is formed to be 1-3 mm, change of the spatial volume
of the flow path of the mist can be reduced, the foggy state of the mist
is maintained, and the mist can be prevented from being liquefied.

[0021] According to a sixth aspect of the present invention, in the
working unit, the forward and backward moving mechanism may be formed of
an air cylinder mechanism driven by air supplied from an compressed air
supply source, the spindle motor may be formed of an air motor driven by
air supplied from the compressed air supply source, and the air supply
section may be supplied with air supplied from the compressed air supply
source.

[0022] According to such a configuration, because the forward and backward
moving mechanism, the spindle motor and the air supply section utilize
the air supplied from a same compressed air supply source, the number of
the supply source (drive source) can be minimized, and the overall unit
can be driven only by air. Accordingly, even in an inconvenient place
where a power source is not available, the unit can be driven as far as
there is a compressed air supply source. Also, because the forward and
backward moving mechanism, the spindle motor and the air supply section
are driven by single power source, the number of parts and assembling
manpower can be reduced and the structure can be simplified, which can
contribute to miniaturization of the overall unit and cost reduction.

[0023] According to a seventh aspect of the present invention, in the
working unit, a flow rate adjusting section adjusting the flow rate of
the air supplied to the mist supply portion and the cutting oil may be
further included.

[0024] According to such a configuration, because the mist mixing portion
has the flow rate adjusting section adjusting the flow rate of the air
and the cutting oil, the flow rate of the air can be adjusted, therefore
the event that the cutting oil cannot be ejected from the communication
hole can be prevented, and only the air can be supplied to the flow path
so as to blow off the cutting oil stored inside to the outside.

[0025] According to the working unit, working device in relation with the
present invention, the mist of the excellent quality can be ejected from
the tip of the tool.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Embodiments of the present invention will be described in detail
based on the following figures, wherein:

[0027] FIG. 1 is a schematic side view with a partial cross-section
showing an example of the working unit in relation with an embodiment of
the present invention;

[0028]FIG. 2 is a front view showing a use condition of the working unit
in relation with an embodiment of the present invention;

[0029]FIG. 3 is a block diagram for illustrating the air flow path of the
working unit;

[0030]FIG. 4A and FIG. 4B are drawings showing the mist mixing portion of
the drilling unit in relation with an embodiment of the present invention
in which FIG. 4A is an essential part enlarged schematic drawing showing
a normal state, whereas FIG. 4B is an essential part enlarged schematic
drawing showing a state when the cutting oil flows backward;

[0031]FIG. 5 is an essential part cross-sectional view showing the
holding section of the drilling unit in relation with an embodiment of
the present invention;

[0032]FIG. 6 is a cross-sectional view taken along the line X-X in FIG.
5;

[0033] FIG. 7 is an essential part enlarged cross-sectional view showing
the communication hole of the collet holder of the drilling unit in
relation with an embodiment of the present invention;

[0034]FIG. 8A and FIG. 8B are drawings showing the drilling unit in
relation with an embodiment of the present invention in which FIG. 8A is
an essential part enlarged cross-sectional view showing the positional
relation of the flow path guide plug and the drill, and FIG. 8B is a
schematic drawing showing the through-holes of the nozzle; and

[0035]FIG. 9 is an essential part enlarged cross-sectional view showing a
reference of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0036] Hereinafter, a working unit 1 in relation with an embodiment of the
present invention will be described with reference to the accompanying
drawings.

[0037] In this connection, the tool can be one that works a workpiece (not
shown) by rotation, and a case in which a drill T is employed will be
described below as an example. Also, the working unit 1 according to an
embodiment of the prevention shown in FIG. 1 is a unit working the
workpiece by rotating and moving forward and backward (reciprocating) the
drill T utilizing a drive force of the hydraulic pressure, pneumatic
pressure, an electric motor and the like, which will be described below
referring to a drilling unit 1A rotating and moving forward and backward
(reciprocating) the drill T by compressed air as an example.

[0038] Further, for the sake of convenience, with reference to the state
in which the grip 1a is held by an operator, the side on which the drill
T is mounted will be referred to as the front side (leading end side),
and the side opposite thereof will be referred to as the rear side, the
side to which the grip 1a is fixed will be referred to as the lower side,
and the side opposite thereof will be referred to as the upper side.

{Constitution of Drilling Unit}

[0039] As shown in FIG. 1, the drilling unit 1A (working unit 1) is a hand
tool with which an operator (not shown) inserts a bush 13 into a
positioning bush Pa formed in a jig plate P for positioning while holding
the grip 1a, locks the bush 13 by a locking screw Pb, and thereby
performs drilling work. The drilling unit 1A is a side-through type unit
with which the drill T is rotated while the mist generated in a mist
mixing portion 8 is supplied to the workpiece (not shown), a feed is
given, and drilling is performed.

[0040] The drilling unit 1A mainly includes a generally cylindrical body
2, a ram 3 internally equipped in the body 2 so as to move forward and
backward, a center bar 40 having an exhaust port E1 in the rear portion
of the ram 3, a forward and backward moving mechanism 6 moving the ram 3
forward and backward, the drill T, a holding section 5 holding the drill
T and moving forward and backward integrally with the ram 3, a spindle
motor M rotating the holding section 5, a mist supply portion 10
supplying foggy mist generated by mixing the cutting oil and the
compressed air to the drill T, a nose piece 12 disposed in the front
portion of the body 2 to cover the drill T, and a bush 13 mounted in the
leading end portion of the nose piece 12 and guiding the tip of the drill
T.

{Constitution of Body}

[0041] The body 2 shown in FIG. 1 is a housing in which the ram 3 moving
reciprocally (feed and return movement), the forward and backward moving
mechanism 6, the spindle motor M and the like are internally equipped.
The body 2 is formed by connecting a front body 21 in which a first
cylinder chamber 61 retracting the ram 3 by the compressed air from a
retracting flow path L21 (refer to FIG. 3) is internally arranged and a
rear body 22 in which a second cylinder chamber 62 advancing the ram 3 by
the compressed air from an advancing flow path L22 (refer to FIG. 3) is
internally arranged. A hydraulic damper D is mounted in the upper portion
of the body 2. The grip 1a having an air supply port 1b communicating
with an air pressure chamber 1c formed in the outer peripheral portion of
the ram 3 is fixed to the lower portion of the body 2.

[0042] In the air pressure chamber 1c, the compressed air introduced from
the air supply port 1b through a motor flow path L11 (refer to FIG. 3) is
temporarily stored, and when the ram 3 initiates feed motion and advances
to allow an inlet flow path In2 of the center bar 40 to communicate with
the air pressure chamber 1c, the compressed air is supplied to the
spindle motor M from the inlet flow path In2 through an inlet flow path
In1 to rotate the spindle motor M.

[0043] The compressed air supplied to the spindle motor M is discharged to
the atmospheric air from an exhaust port E1 through an exhaust flow path
(not shown). The exhaust port E1 is provided with an exhaust air throttle
valve E2 restricting the exhaust air quantity for adjusting the speed of
the spindle motor M.

[0044] As shown in FIG. 1, the center bar 40 is formed of a shaft bar
member extended so as to be screwed into the rear end portion of the ram
3 to block the rear end portion of the ram 3. The center bar 40 includes
the exhaust flow path (not shown), the exhaust port E1, and the motor
flow path L11 (refer to FIG. 3). In the center bar 40, an adjust screw 42
is provided through a screw support plate 41.

{Constitution of Ram}

[0045] The ram 3 is a generally cylindrical member moving the drill T
forward and backward by the compressed air through the holding section 5,
and is internally equipped in the body 2 so as to move forward and
backward. The ram 3 is slidably supported by the leading end portion,
center portion and rear end portion of the body 2 through seal members
(not shown). In the ram 3, a flange-shaped enlarged diameter portion (not
shown) sliding in the front-rear direction inside the body 2 by the
compressed air is formed in the center portion of the outer peripheral
portion.

{Constitution of Adjust Screw and Hydraulic Damper}

[0046] The adjust screw 42 can adjust the feed rate of the ram 3 by
pressing the hydraulic damper D accompanying the advancing movement of
the ram 3.

[0047] With respect to the hydraulic damper D, two kinds, for example, of
a damper adjusting the feed rate of the ram 3 and a damper adjusting the
creep speed feed rate in the drilling work are arranged side by side on
the body 2.

{Constitution of Forward and Backward Moving Mechanism}

[0048] As shown in FIG. 1, the forward and backward moving mechanism 6 is
formed, for example, of an air cylinder mechanism making the ram 3,
holding section 5, and the drill T advance and retract by the compressed
air supplied to the first cylinder chamber 61 or the second cylinder
chamber 62 formed between the outer peripheral portion of the ram 3 and
the inner peripheral portion of the body 2 from an compressed air supply
source 4 through an air flow path L (refer to FIG. 3).

[0049] The first cylinder chamber 61 is formed on the front side of the
enlarged diameter portion (not shown), and the compressed air for
retracting is introduced thereinto through the retracting flow path L21
(refer to FIG. 3) to retract the ram 3. The second cylinder chamber 62 is
formed on the rear side of the enlarged diameter portion (not shown), and
the compressed air for advancing is introduced thereinto through the
advancing flow path L22 (refer to FIG. 3) to advance the ram 3.

{Constitution of Spindle Motor}

[0050] The spindle motor M is a motor making the ram 3 rotate the drill T
through the holding section 5, and is formed of, for example, an air
motor rotated by the compressed air supplied to an air motor chamber Ma
from the compressed air supply source 4 (refer to FIG. 3) through the air
supply port 1b. A collet 51 and a collet holder 52 of the holding section
5 holding the drill T are connected to the leading end portion of a
spindle Mb of the spindle motor M by a flat countersunk head screw 57.

{Constitution of Air Flow Path}

[0051] As shown in FIG. 3, an air flow path L is a flow path supplying the
compressed air supplied to the air supply port 1b from the compressed air
supply source 4 to the drill T and the like through the spindle motor M,
the forward and backward moving mechanism 6, and the mist supply portion
10. The air flow path L includes the air supply port 1b communicating
with the compressed air supply source 4, a first flow path L1 supplying
the compressed air from the air supply port 1b to the spindle motor M and
the like, a second flow path L2 supplying the compressed air from the air
supply port 1b to the forward and backward moving mechanism 6 and the
like, an air for mist supply path L3 supplying the compressed air from
the air supply port 1b to a flow rate adjusting portion 7, an air and oil
split-flow supply pipe 11 supplying the compressed air from an air flow
rate adjusting portion 72 of the flow rate adjusting portion 7 and the
cutting oil from a cutting oil quantity adjusting screw portion 74 (oil
supply portion) to the mist mixing portion 8 respectively to generate the
mist, and a communication hole 52d and a mist supply path 55a supplying
the mist generated in the mist mixing portion 8 to the drill T through
the collet holder 52 (not shown) and a flow path guide plug 55.

[0052] The air supply port 1b is a connection port to which a supply pipe
connected to the compressed air supply source 4 arranged outside and
supplying the compressed air of approximately 0.5-0.6 MPa is connected,
and is formed in the lower end portion of the grip L1 (refer to FIG. 1).
The air supply port 1b communicates with the first flow path L1, the
second flow path L2, and the air for mist supply path L3 respectively.

[0053] Further, because the first flow path L1, the second flow path L2,
and the air for mist supply path L3 are connected in parallel
respectively, adjustment of the speed of the spindle motor M (spindle
speed), adjustment of the reciprocating movement speed (feed rate) of the
ram 3, and adjustment of the flow rate of the compressed air supplied to
the mist mixing portion 8 performed by the air flow rate adjusting
portion 72 can be respectively performed independently.

[0054] As shown in FIG. 3, the first flow path L1 includes the motor flow
path L11 for driving the spindle motor M, a second advancing flow path
L12 branched from the motor flow path L11 and advancing the ram 3 (refer
to FIG. 1). The motor flow path L11 includes the inlet flow path In1
(refer to FIG. 1) formed in the axial direction from the leading end
portion of the center bar 40 and the inlet flow path In2 (refer to FIG.
1) communicating with the inlet flow path In1. The second advancing flow
path L12 supplies the compressed air to the rear end portion of the ram 3
(refer to FIG. 1) and advances the ram 3.

[0055] The second flow path L2 includes the retracting flow path L21
supplying the compressed air for retracting the ram 3 (refer to FIG. 1),
the holding section 5, and the drill T to the first cylinder chamber 61,
a return button R for making the compressed air flow through the
retracting flow path L21, the advancing flow path L22 supplying the
compressed air for advancing the ram 3 (refer to FIG. 1), the holding
section 5, and the drill T to the second cylinder chamber 62, a pressure
regulator PV arranged in the advancing flow path L22, a pressure
compensated flow control valve SP adjusting the flow rate of the
compressed air to adjust the advancing and retracting speed of the ram 3
(refer to FIG. 1), the holding section 5, and the drill T, and a start
button S for operating the ram.

[0056] The pressure regulator PV is mounted behind the grip 1a (refer to
FIG. 1), and can adjust the advancing thrust of the ram 3 by reducing the
pressure of the compressed air. The pressure compensated flow control
valve SP can finely adjust the feed rate of quick forward movement of the
ram 3.

{Constitution of Mist Supply Portion}

[0057] As shown in FIG. 3, the mist supply portion 10 is constituted to
include the mist mixing portion 8 generating the mist which is the
fog-like mixture of the cutting oil supplied to the drill T and the
compressed air, the air supply port 1b supplying the compressed air to
the mist mixing portion 8 through the air flow path L, an oil supply
section (an oil supply pipe 11b) supplying the cutting oil to the mist
mixing portion 8, an air supply section (an air supply pipe 11a)
supplying the compressed air to the mist mixing portion 8, a flow rate
adjusting section (flow rate adjusting portion 7) adjusting the flow rate
of the compressed air and the cutting oil supplied to the mist mixing
portion 8, and the communication hole 52d and the mist supply path 55a
supplying the mist to through-holes Tc (refer to FIG. 5) of the drill T.

{Constitution of Air for Mist Supply Portion}

[0058] As shown in FIG. 1 and FIG. 3, the air for mist supply path L3 is
an air supply device supplying the compressed air to the mist mixing
portion 8. The air for mist supply path L3 includes a first air supply
pipe L31 whose upstream side is connected to the air supply port 1b and
downstream side is connected to a hand valve 71, the hand valve 71
opening/closing the downstream side of the first air supply pipe L31, a
second air supply pipe L32 whose upstream side is connected to the hand
valve 71 and downstream side is connected to the air flow rate adjusting
portion 72, and the air flow rate adjusting portion 72 adjusting the flow
rate of the compressed air supplied to the mist mixing portion 8.

{Constitution of Hand Valve}

[0059] The hand valve 71 is a manual valve having a opening/closing knob
opening and closing the air for mist supply path L3. When the hand valve
71 is opened, the compressed air flows from the air supply port 1b to the
first air supply pipe L31, the hand valve 71, the second air supply pipe
L32, the air flow rate adjusting portion 72, the air and oil split-flow
supply pipe 11 and the mist mixing portion 8, is mixed with the cutting
oil in the mist mixing portion 8 to become the mist, flows through the
communication hole 52d inside the holding section 5, the mist supply path
55a and the through-holes Tc, and the mist is ejected from the tip of the
drill T. When the hand valve 71 is closed, supply of the mist also stops.

{Constitution of Air Flow Rate Adjusting Portion}

[0060] As shown in FIG. 1, the air flow rate adjusting portion 72 is
constituted to include an air inlet port (not shown) formed on the side
surface of a flow rate adjusting portion body 7a of the flow rate
adjusting portion 7, and an adjusting screw 72a (refer to FIG. 2)
adjusting the flow rate of the compressed air entering into the flow rate
adjusting portion body 7a from the air inlet port.

[0061] The adjusting screw 72a (refer to FIG. 2) is a volume capable of
adjusting the flow rate of the compressed air entering the mist mixing
portion 8 from the second air supply pipe L32 by turningly adjusting the
screwed quantity of screwing with the female thread portion (not shown)
formed in the air inlet port.

[0063] As shown in FIG. 1, the cutting oil tank 73 is a generally
cylinder-like tank and is attached to the upper portion of the body 2 by
an attaching fixture. The cutting oil tank 73 is provided with a
branching portion 73a supplying the compressed air having passed the hand
valve 71 to the cutting oil tank 73 side, a pressurizing piston 73b
pressurizing the cutting oil by the compressed air taken from the
branching portion 73a, and a cylindrical tank 73c in which the
pressurizing piston 73b is internally arranged so as to move forward and
backward. An opening of the cutting oil tank 73 communicates with the
mist mixing portion 8 and the cutting oil supply port 75 to allow the
cutting oil to enter and exit.

[0064] As shown in FIG. 2, the cutting oil supply port 75 is constituted
so as to connect an injecting connection pipe 76c to a supply port 75a to
which the cutting oil feeder 76 is connected and a coupler connection
port formed in the supply port 75a.

[0065] The cutting oil feeder 76 is formed of an oil syringe ejecting the
cutting oil to the cutting oil tank 73. The cutting oil feeder 76
includes a cylindrical container 76a containing the cutting oil, a piston
rod 76b pushing out the cutting oil inside the container 76a, and the
injecting connection pipe 76c whose leading end is internally fitted to
the supply port 75a with the base portion communicating with the inner
bottom of the container 76a.

{Constitution of Mist Mixing Portion}

[0066] As shown in FIG. 4A, the mist mixing portion 8 is a mixing nozzle
device generating the mist by mixing the cutting oil and the compressed
air. The mist mixing portion 8 is constituted to mainly include an air
nozzle 81 ejecting the compressed air, an oil nozzle 82 inserted into the
air nozzle 81 and ejecting the cutting oil, an injection pipe 83 shown in
FIG. 5, a wheel cap 84 covering the mist mixing portion 8, and a nipple
85 connecting the mist mixing portion 8 with a coolant cover 56.

{Constitution of Holding Section}

[0067] The holding section 5 is a section holding the drill T and forming
a flow path supplying the mist generated in the mist mixing portion 8 to
the drill T. The holding section 5 is constituted to mainly include the
coolant cover 56, the collet 51 holding the drill T, the collet holder 52
having an inner cylindrical portion 52a having a stepped cylinder shape
to which the collet 51 and the flow path guide plug 55 are internally
fitted and formed with the communication hole 52d through which the mist
supplied from the mist supply portion 10 is introduced from the inner
cylindrical portion 52a to the outer peripheral portion, the flow path
guide plug 55 formed with the mist supply path 55a through which the mist
flows, the flat countersunk head screw 57 connecting the collet holder 52
with the spindle Mb, a collet nut 58 fixing the collet 51 to the collet
holder 52, and a positioning pin 92 fixing the flow path guide plug 55 at
a predetermined position inside the collet holder 52.

{Constitution of Coolant Cover}

[0068] As shown in FIG. 5, the coolant cover 56 is a member making the
mist mixing portion 8 communicate with the communication hole 52d formed
in the collet holder 52. The coolant cover 56 is formed of a member of a
stepped cylinder shape composed of a small diameter portion and a large
diameter portion. In the coolant cover 56, a connection portion 56a to
which a leading end side connection portion 8a of the mist mixing portion
8 is connected and formed in a position agreeing with the position of the
communication hole 52d, and annular grooves 56b, 56c into which O rings
O1, O2 arranged apart from each other in the axial direction with respect
to the connection portion 56a are fitted are formed.

[0069] As shown in FIG. 5 and FIG. 6, there is a small gap C between the
inner wall surface of the coolant cover 56 and the outer peripheral
surface of the collet holder 52 between the O rings O1 and O2, however
two O rings O1, O2 are configured to prevent the mist from leaking to the
outside. The coolant cover 56 is fixed to the ram 3 by a setscrew.
Therefore the coolant cover 56 moves forward and backward integrally with
the ram 3.

[0070] As shown in FIG. 6, the gap C is a ring-like space formed between
the inner wall surface of the coolant cover 56 and the outer peripheral
surface of the collet holder 52 rotating integrally with the spindle Mb,
and communicates with the mist mixing portion 8 and the communication
hole 52d at all time. Therefore, the gap C acts as a means of escape by
relaxing instantaneous rise of the flowing resistance of the mist caused
because the mist supplied from the mist mixing portion 8 escapes threinto
when the communication hole 52d shifts from the position of the pipeline
inside the leading end side connection portion 8a of the mist mixing
portion 8 at the time the collet holder 52 rotates. As a result of it,
the mist can be prevented from colliding with the wall surface of the
flow path and being liquefied in the gap between the leading end side
connection portion 8a of the mist mixing portion 8 and the communication
hole 52d.

[0071] Also, because the gap C is formed between the inner wall surface of
the coolant cover 56 and the outer peripheral surface of the collet
holder 52, the space becomes of a non-contact state, therefore the
frictional resistance is reduced and rotation of the collet holder 52
becomes excellent.

{Constitution of Collet and Collet Nut}

[0072] As shown in FIG. 5, the collet 51 is a generally cylindrical member
to which a rear end surface Tb side of the drill T is attached and has a
taper portion internally fitted to an expansion portion 52k expandingly
formed in the inner cylindrical portion 52a of the collet holder 52 on
the outer peripheral surface. The collet 51 is provided with a plurality
of slots 51a to facilitate elastic deformation of the collet 51 in the
radial direction and a drill holding hole 51b into which the drill T is
inserted.

[0073] The collet nut 58 is a fixture fixing the collet 51 to the collet
holder 52, and has a female thread portion (not shown) screwed with a
male thread portion 52i of the collet holder 52 in a state the head
portion of the collet 51 is internally fitted.

{Constitution of Collet Holder}

[0074] As shown in FIG. 5, the collet holder 52 is a generally cylindrical
member forming the main body of the holding section 5 and formed with a
supply path supplying the mist supplied through the nipple 85 to the
through-holes Tc of the drill T inside. The collet holder 52 is formed
with the inner cylindrical portion 52a in which a front side opening end
52b and a rear side opening end 52 c communicate with each other in the
axial direction, the communication hole 52d formed diagonal with respect
to the axial direction from an outer opening end 52g formed on the outer
peripheral surface of the collet holder 52 toward an inner opening end
52f, a step portion 52e formed in a step shape by narrowing the diameter
in the generally central portion inside the inner cylindrical portion
52a, the male thread portion 52i, and a pin mounting hole 52j in which
the positioning pin 92 is mounted.

[0075] The collet holder 52 is configured that the mist is supplied to the
outer opening end 52g of the communication hole 52d, passes through the
through-holes Tc of the drill T via the mist supply path 55a formed in
the flow path guide plug 55 inside the collet holder 52, and is supplied
to a working portion from a cutting edge.

[0076] Into the inner cylindrical portion 52a, starting from the step
portion 52e toward the front side, the flow path guide plug 55 provided
with a rubber member 91 and the collet 51 mounted with the drill T are
inserted in this order. As shown in FIG. 8A, the mist supply path 55a of
the flow path guide plug 55 internally fitted to the inner cylindrical
portion 52a (refer to FIG. 5) is arranged in a state formed from the
inner opening end 52f of the communication hole 52d toward the
through-holes Tc on the rear end surface Tb of the drill T. As shown in
FIG. 5, the front end portion of the spindle Mb is inserted into the rear
side of the inner cylindrical portion 52a, and the spindle Mb is fixed to
the collet holder 52 by the flat countersunk head screw 57 (fastener). In
the step portion 52e, the inner opening end 52f of the communication hole
52d opens, and the head portion of the flat countersunk head screw 57
(fastener) is attached.

{Constitution of Flat Countersunk Head Screw}

[0077] As shown in FIG. 5 and FIG. 8A, the flat countersunk head screw 57
is arranged so as to engage with the step portion 52e and to block the
inner cylindrical portion 52a in order not to be a state the head portion
of the flat countersunk head screw 57 projects forward from the step
portion 52e inside the inner cylindrical portion 52a. The rubber member
91 is arranged between the flat countersunk head screw 57 and the flow
path guide plug 55 in a state securely sticking with each other. In this
case, the rubber member 91 is firmly adhered by rubber-baking to a recess
portion 55d formed on the rear end surface of the flow path guide plug 55
in a state abutting upon the head portion of the flat countersunk head
screw 57, however it may be firmly adhered to the head portion of the
flat countersunk head screw 57.

{Constitution of Positioning Pin}

[0078] The positioning pin 92 is inserted into a pin mounting hole 52j,
and its tip engages with a keyway-like positioning portion 55e formed on
the outer peripheral surface of the flow path guide plug 55, and thereby
the position of the communication hole 52d of the collet holder 52 and
the position of the mist supply path 55a of the flow path guide plug 55
are aligned with each other so as to form a diagonal straight line.

{Constitution of Communication Hole}

[0079] As shown in FIG. 5, the communication hole 52d is formed diagonal
with respect to the axial direction from the outer opening end 52g of the
collet holder 52 to which the mist is supplied toward the inner opening
end 52f side. As shown in FIG. 7, in the communication hole 52d, the
outer opening end 52g opens to an oil pocket 52h notched and formed on
the outer peripheral surface of the collet holder 52. As shown in FIG.
8A, the inner opening end 52f of the communication hole 52d is arranged
in a state agreeing with an upstream side opening end 55b of the flow
path guide plug, 55 on a same straight line, and is arranged in the
continuous state to allow smooth flow of the mist.

{Constitution of Flow Path Guide Plug}

[0080] As shown in FIG. 5, the flow path guide plug 55 is a generally
cylindrical member having the mist supply path 55a drilled diagonal with
respect to the axial direction and internally fitted to the inner
cylindrical portion 52a. As shown in FIG. 8A, the flow path guide plug 55
is arranged so that the mist entering the outer opening end 52g (refer to
FIG. 5 and FIG. 7) of the communication hole 52d continuously flows from
the communication hole 52d to the through-holes Tc of the drill T through
the mist supply path 55a.

[0081] In other words, the mist supply path 55a is formed so that a
portion of the mist supply path 55a from the upstream side opening end
55b to a downstream side opening end 55c is formed diagonal with respect
to the axial direction toward the through-holes Tc on the rear end
surface Tb of the drill T, and that the mist entering the upstream side
opening end 55b flows straight toward the through-holes Tc. Also, the
mist supply path 55a and the communication hole 52d are arranged so as to
form a straight line toward the through-holes Tc, and this state is
maintained by the positioning pin 92.

[0082] The inside diameter of the mist supply path 55a of the flow path
guide plug 55 is formed to be 1-3 mm, preferably 1.5-2 mm, and more
preferably 2 mm.

[0083] Also, the inside diameter of the mist supply path 55a is not
limited to the above-mentioned figures, and may be of appropriate
dimension according to the working diameter and the inside diameter of
the oil hole of the drill T. For example, when the working inside
diameter is 5-16 mm, the inside diameter of the oil hole of the drill T
that works is basically 0.6-1.7 mm ( 1/10 of the working diameter plus
0.1 mm).

{Constitution of Nose Piece, Bush, and Drill}

[0084] As shown in FIG. 1, the nose piece 12 is a cover member disposed in
the front portion of the body 2 and covering the holding section 5 and
the rear end portion side of the drill T.

[0085] The bush 13 is a cylindrical member attached to the leading end
portion of the nose piece 12 and supporting the drill T.

[0086] As shown in FIG. 5 and FIG. 8B, the drill T is a tool working a
workpiece, and has a plurality of the through-holes Tc through which the
mist or the compressed air flows extending from the cutting blade portion
of a front end surface Ta to the rear end surface Tb.

[Action]

[0087] The motion of the drilling unit 1A in relation with the present
embodiment constituted as described above will be described referring to
a reference shown in FIG. 9.

{Reference}

[0088]FIG. 9 is an essential part enlarged cross-sectional view showing a
reference of the present invention. First, the reference will be
described referring to FIG. 9.

[0089] As shown in FIG. 9, a drilling unit 100 of the reference is
equipped with a collet 110 holding a drill 200 so as to form a large
inner space 123 in an inner cylindrical portion 122 inside a collet
holder 120. In the inner space 123, a head portion of a hexagon socket
head cap bolt 300 for fixing a spindle is arranged in a state projecting
from the inner wall surface. On the outer peripheral surface of the
collet holder 120, four communication holes 121 in a straight shape
through which the mist is supplied from a mist mixing portion 400 are
formed, and communicate with the inner space 123.

[0090] Using the drilling unit 100 constituted as described above, an
experiment was conducted in which the mist generated in the mist mixing
portion 400 was supplied to through-holes 210 of the drill 200 from the
four communication holes 121 through the inner space 123. Then, the foggy
mist was not ejected from the tip of the drill 200, and only the
compressed air was ejected. Also, because the flow path area of the four
communication holes 121 in a straight shape and the inner space 123 was
wide and the head portion of the hexagon socket head cap bolt 300
projected into the flow path, the mist collided with the head portion,
and as a result of it, the mist was stored in a liquefied state, and
occasionally, the cutting oil was discharged successively from the tip of
the drill 200.

{Action According to the Present Invention}

[0091] The present invention is a modification of the reference allowing
excellent mist to be ejected from the tip of the drill T. Its action will
be described below.

[0092] In the drilling unit 1A in relation with the present embodiment, as
shown in FIG. 1, when the start button S is pressed, the compressed air
supplied to the air supply port 1b from the compressed air supply source
4 passes the advancing flow path L22 shown in FIG. 3 and is supplied to
the second cylinder chamber 62 of the forward and backward moving
mechanism 6 and the spindle motor M through the pressure regulator PV and
the pressure compensated flow control valve SP, the forward and backward
moving mechanism 6 advances, and the spindle motor M rotates.

[0093] When the ram 3 shown in FIG. 1 advances to a position where the
inlet flow path 1n2 and the air pressure chamber 1c communicate with each
other, the compressed air is supplied to the spindle motor M through the
inlet flow path In2 and the inlet flow path In1, and the spindle motor M
rotates. Thus, the feed is given to perform drilling while the drill T is
rotated.

[0094] Also, when the hand valve 71 is opened, the compressed air flows
from the air supply port 1b to the first air supply pipe L31, the hand
valve 71, the second air supply pipe L32, the air flow rate adjusting
portion 72, the air and oil split-flow supply pipe 11, and the mist
mixing portion 8, is mixed with the cutting oil in the mist mixing
portion 8 to be formed into the mist, flows through the communication
hole 52d, the mist supply path 55a, and the through-holes Tc, and the
mist is ejected from the tip of the drill T.

[0095] As shown in FIG. 5, the communication hole 52d and the mist supply
path 55a formed in an equal diameter are arranged on one diagonal
straight line from the outer opening end 52g of the outer peripheral
portion of the collet holder 52 toward the through-holes Tc of the drill
T existing in the direction of the axis through the downstream side
opening end 55c, and therefore the mist generated in the mist mixing
portion 8 flows so as to smoothly enter the through-holes Tc. Thus, the
mist is allowed to flow straight linearly via the shortest distance, and
collision with the wall surface and the like inside the flow path is
eliminated, and the flowing resistance is small. As a result of it,
liquefying of the mist can be eliminated.

[0096] Further, when the flow path guide plug 55 is to be assembled to the
collet holder 52, as shown in FIG. 5 and FIG. 8A, the flow path guide
plug 55 is internally fitted to the inner cylindrical portion 52a of the
collet holder 52 having one communication hole 52d with the mist supply
path 55a side up and the pin mounting hole 52j side down in a state the
rear end surface Tb of the drill T abuts upon an enlarged diameter
surface 55f of the flow path guide plug 55, and the state is maintained
by engaging the positioning pin 92 with the pin mounting hole 52j. Then
the communication hole 52d and the mist supply path 55a agree with each
other, and a generally pipe-like continuous flow path is formed.

[0097] Accordingly, the flow path volume of the flow path through which
the mist flows from the communication hole 52d as far as the
through-holes Tc of the drill T through the mist supply path 55a is less
than the flow path volume in the reference. As a result of it, the mist
smoothly flows toward the mist supply path 55a and the through-holes Tc
without being temporarily stored inside the flow path guide plug 55 and
without colliding with the wall surface and the like, the flowing
resistance is small, and therefore the mist is not liquefied.

[0098] Because the front end surface Ta of the drill T is arranged so as
to abut upon the tapered opening portion of the flow path guide plug 55,
the mist ejected from the mist supply path 55a is ejected so as to be
introduced into the through-holes Tc. Also, as shown in FIG. 88, because
the pitch distance d of the through-holes Tc of the drill T is narrow,
the mist having passed the mist supply path 55a of the flow path guide
plug 55 enters the through-holes Tc easily. As a result of it, the mist
is ejected from a front end surface Ta of the drill T in an excellent
mist state.

[0099] Also, when the cutting oil is stored in the mist supply path 55a
inside the holding section 5, the cutting oil quantity adjusting screw
portion 74 is operated to stop the flow of the cutting oil and to supply
only the compressed air, thereby, as shown in FIG. 4B, the cutting oil
present in the mist mixing portion 8 can be made flow backward into the
oil supply pipe 11b, and the cutting oil stored inside the flow path can
be blown off to the downstream side by the ejected air to allow to be
discharged to the outside from the tip of the drill T.

[0100] On the other hand, when the return button R is pressed, the
compressed air is supplied from the compressed air supply source 4 to the
first cylinder chamber 61 of the forward and backward moving mechanism 6
through the retracting flow path L21 (refer to FIG. 3) via the air supply
path 1b, and the ram 3 retracts. When the ram 3 retracts further beyond
the position where the inlet flow path In2 and the air pressure chamber
1c communicate with each other, communication of the inlet flow path 1n2
and the air pressure chamber 1c is intercepted thereby, supply of the
compressed air to the spindle motor M is stopped, and therefore the motor
M stops.

[0101] Also, the return button R retracts during an advancing motion in
the manual motion. Further in the auto-return motion, the return button R
automatically retracts when the ram 3 reaches a predetermined advance
end.

[0102] In addition, the present invention is not limited to the
above-mentioned embodiments, a variety of modifications and alterations
are possible within the scope of its technical thought, and it will be
needless to mention that the present invention covers such modified and
altered invention.

[0103] For example, with respect to a working unit 1 having a reciprocally
moving body, an embodiment of the present invention was described citing
a case of feeding the ram 3 of such a drilling unit as shown in FIG. 1 as
an example, however the present invention is not limited to it and can be
applicable as far as a machine has a reciprocally moving body that moves
forward and backward, and other type of units will do.

[0104] The working unit 1 can be a machine equipped with a reciprocally
moving body such as the ram 3 and the like that moves forward and
backward, or can be a machine mounted with the ram 3 moving an object
such as a tool and a workpiece forward and backward, and what activates
the reciprocally moving ram 3 and for which application the working unit
is used are not specifically limited.

[0105] That is to say, the spindle motor M can be of any type as far as it
rotates the ram 3, the holding section 5 and the drill T, and it can be a
hydraulic motor, electric motor and the like for example.

[0106] Also, the forward and backward moving mechanism 6 can be of any
type as far as it is a device moving the ram 3, the holding section 5 and
the drill T forward and backward, and can be of a type employing other
type of mechanism such as a hydraulic cylinder mechanism, a motorized
gear mechanism and the like.

[0107] Although the above-mentioned embodiment was described citing the
drill T as an example of the tool, other types of tools are applicable as
far as they work a workpiece by rotating and reciprocally moving a rotary
tool such as a tap, reamer, end mill, and the like.

Patent applications by Hideki Uchiuzo, Namerikawa-Shi JP

Patent applications by Minoru Ihara, Uozu-Shi JP

Patent applications by SUGINO MACHINE LIMITED

Patent applications in class Conducting channel extending to end of tool

Patent applications in all subclasses Conducting channel extending to end of tool